Young Kanjuro was a stagehand!
Kuroko (Japanese: 黒子, lit. "black child") are stagehands in traditional Japanese theatre, who dress all in black.
In kabuki, the
kuroko serve many of the same purposes as running crew. They move scenery and props on stage, aiding in scene changes and costume changes. They will also often play the role of animals, will-o-the-wisps, or other roles which are played not by an actor in full costume, but by holding a prop.
Kuroko wear all black, head to toe, in order to imply that they are invisible and not part of the action onstage.
https://en.wikipedia.org/wiki/Kuroko
So Kanjuro went from being an invisible stagehand to a starring role. His costume started as a background character, but as an adult he has a full Kabuki star outfit and face paint.